FIELD OF THE INVENTION
The invention relates to a device for adjusting printing unit cylinders in printing units of rotary printing presses, particularly when a material web remains in the printing units.
The published European Patent Document EP 0 596 244 A1 is concerned with a printing unit having a releasable bearing attachment. The printing unit includes a blanket cylinder, a bearing and an assembly gate. A sleeve-shaped printing blanket is disposed on the blanket cylinder, and the bearing has a bearing housing which is fastened to a stub shaft at an end of the blanket cylinder. The assembly gate includes a gate which is rotatably mounted on a frame wall of the printing unit. In a closed position, the gate covers an opening formed in the frame wall and, in an opened position, the opening is exposed. The bearing housing is clamped by a clamping device to the gate when the blanket cylinder rotates during the printing process. The clamping device has a first clamping jaw which is fastened to the gate, and a second clamping jaw disposed on the gate so as to be movable relative to the first clamping jaw. The first clamping jaw is in contact with the bearing housing, and the second clamping jaw is movable into and out of contact with the bearing housing when the gate is closed. During disengagement, the assembly gate is moved with the blanket cylinder.
The published European Patent Document EP 0 625 423 A1 discloses a printing unit with an oblique adjustment device and a shut-down device. A printing unit includes a frame, a first and a second support bracket and a lower and an upper plate cylinder. The first support bracket is movably mounted on the frame. An end of the upper plate cylinder is mounted so that it moves with the first support bracket. The second support bracket is also movably mounted on the frame. An end of the lower printing unit cylinder is mounted so that it moves with the second support bracket. The printing unit further includes an oblique adjustment device and a shut-down device. The oblique adjustment device moves the support brackets independently of one another transversely to the frame. The shut-down device includes an adjustment cylinder and a piston rod, which are disposed between the two support brackets. The adjustment cylinder and the piston rod are pivotally connected to the support brackets and can be pivoted with respect to these support brackets when the latter are transversely adjusted by the oblique adjustment device. Via the shut-down device, the support brackets can be obliquely disposed independently of one another, while they remain connected to one another, however, for the shut-down operation.
With the foregoing construction, the blanket cylinders always come into contact with one another automatically upon the engagement of the upper and the lower plates, respectively, and the blanket cylinder, respectively. This forcible coupling of the blanket cylinder adjustment quite considerably aggravates or complicates the automatization of the printing-form exchange. The material web remaining between the blanket cylinders in the printing unit can tear during the printing-form exchange and during the application or mounting of the printing form on the plate cylinder, respectively, which results in a costly reinsertion of the material web and accompanying time loss.
A remedy may indeed be provided by removing the lower printing unit cylinder and the blanket sleeve on the lower printing unit cylinder, respectively, in order to exchange the printing form on the upper plate cylinder, and the reverse, however, this is likewise a time-consuming solution.